Automated equipment has long been available to wind webs of photographic film, paper, and other materials tightly about cores. The web is commonly wound onto a core through a nip between the core or growing web roll and another roller. This helps wind the film tightly. The winding mechanisms include provisions allowing for growth of the web roll. U.S. Pat. No. 4,697,755 discloses a mechanism in which a core is pivoted as the size of the web roll changes. U.S. Pat. No. 3,712,554 discloses a winding mechanism in which a builder roller is pivoted. U.S. Pat. No. 5,256,232 translates a builder roller on a slidable carriage. The builder roller also pivots. This approach also has the advantage of allowing separate adjustment of tension on the web and pressure at the nip. This approach uses an idler roller to turn the web and direct the web onto the builder roller.
Prior to winding, the web is cinched onto the core. This can be done by inserting the free end of the web into a slot in the core, but this can lead to deformation or damage to the end of the web. This is undesirable in some uses, such as film cinematography, in which the free end of the film can have otherwise usable images. The cinching can be provided without the use of a slot or the like, by gripping the leading portion of the web prior to and during the winding of an initial turn. This adds complexity in that the elements used to initially grip the leading portion of the film cannot be left in positions that would interfere with the growing web roll.
U.S. Pat. No. 5,248,107 discloses a film winding apparatus, in which a core is supported on a pair of drums and is held in place by a rider roller. For cinching, a nip roller is brought into contact with the web to hold the web in position. The leading portion is then wrapped around the core by a wrapping table, a slide roller, and a wrapping roller. The wrapping table and slide roller are first moved vertically. The slide roller is then moved horizontally to push the web against the core. The wrapping roller is then brought toward the web to push the web against the core. The wrapping roller is then rolled circumferentially around 45 degrees of the core to wrap that part of the leading portion against the core. The nip roller, wrapping table, slide roller, and wrapping roller are all moved to their original positions after cinching. This approach uses many parts and moves those parts in a complex manner.
U.S. Pat. Nos. 2,989,265 and 5,690,264 disclose apparatus having center pivoted web rollers.
It would thus be desirable to provide improved winding apparatus and methods that cinch with little or no damage to the free end of the web, in a way that is comparable with a carriage mounted builder roller.